Eukaryotic -- distinct nucleus, seperates transcription and translation, allows mRNA processing

Prokaryotic -- lacks nucleus

Connected to ER

Associated with ribosomes

Connected at PORES to Inner Membrane

ER membrane proteins can diffuse into this membrane

Cisternae(Perinuclear Space)

1-fibrous network(Lamins A,B,C)

2-present beneath inner membrane of all cells

3-binds to specific membrane proteins and specific chromatin regions

4-gives nucles shape

5-phosphorylation leads to breakdown of nuclear envelope  before and during mitosis

1-50 different nucleoporins(proteins)

2-by EM(?), 8 pairs of subunits

3-3-4000/nucleus

4-likely held in place by lamina, may have specific arrangement

5-allows passage less than 9nm

6-larger proteins actively transported(immature ribosomal particles & RNA polymerases)

7-NLS signal, 4-8 hydrophobic AA

1-dark staining region

2-ribosome synthesis(size proportional to activity)

3-as many as 10 form after mitosis

-->corresponds to # of different gene coding regions)

4-fuses as cell progresses

5-contains 3 distinct regions(pale, fibrillar, granular)

contains DNA of nucleolar organizer region(Pars Amphora)

composed of repeated sequences of genes coding for rRNA

200 copies of rRNA encoding DNA on 5 different chromosomes(10 distinct regions)

1-fine fibres 5nm thick

2represents rRNA transcribed from DNA

3)rRNA initially single strand, then fragmented prior to subunit assembly

1-15nm granules

2where rRNA precursors found

3-rRNA complexed with 70 proteins which compromise ribosomal subunits

4-proteins brought in from cytoplasm

5-immature ribosomal subunits exit to cytoplasm and reach final maturity

1-dark staining

2-highly coiled/condensed, inactive DNA form

3-near nuclear envelope, except where there's pores

1-light staining

2-uncoiled, transcriptionally active

3-cells w/ a large euchromatic nucleus highly active in protein synthesis

DNA

Histones

Non-histone Chromosomal Proteins

1-22 chromosomes +1 sex =>46 total in diploid nucleus

2-R or L helix

3-partial cysteine methylation(specific for cell types)

4-methylation pattern passed on by maintenance methylase

5-methylation affects transcription, responsible for genomic imprinting

6-3.2x10⁹ base pairs(1-2% code protein/RNA)

7-30,000 genes, most with introns

8-LArge sequence blocks conserved b/w species

1-5 types of proteins w/ high (+) charge

2-major component of chromatin

3-highly conserved, often chemically modified

1-minor component of chromatin

2-hundreds or thousands, recognize specific DNA sequences

3-function in regulation of gene expression - gene regulatory proteins or transcription factors

1-Nucleosome

2-30nm Chromatin Fiber

3-Looped Domains

4-Condensed Chromosome

1-8 histones (4 pairs of different ones)

2-final type on the outside of this complex, serves as an extending arm

3-phosphorylation initiates chromosome condensation during mitosis

30nm fiber forms large 400nm loops

theory is that nucleus contains "scaffolding" which maintains loops and organizes chromosomes

1-loops in tight helix pointing outwards

2-telomeres-ends of chromosomes

3-centromere-restricted region

4-karyotype-display of chromosomes during mitosis

1-DNA->RNA

2-7-10% DNA transcribed to RNA, only 1-2% of DNA sequences reaches cytoplasm as mRNA

3-Gene regulatory proteins recognize protein coding DNA regions

4-DNA is still somewhat recognized when complexed w/ histones

1-proteins which bind specific sequences and regulate transcription

2-zinc fingers - class of GRP's w/stretches of AAs which bind zinc and recognize specific DNA sequences

3-Leucine Zipper - GRP class w/ a series of leucine along side of molecule, allowing heterodimer formation

4-this allows a small number of proteins to control a large number of different genes

bind regulatory sequences of DNA near start of gene(enhancers or gene control regions)

factors form a complex that activates or inhibits RNA  polymerase

Section of DNA that RNA polymerase binds to

Regulatory sequences can sometimes be located far away from promoter due to folding

Capping

Poly-A-Tail

Splicing

7-methyl guanosine residue linked by triphosphate bond to the end of mRNA -- signal attachment for ribosomes

cap at 5'

Approximately 200 adenylate residues at other end of RNA chain

influences export and or retards degradation

snRNP's remove introns in the hnRNA from the mRNA

snRNP's organized into splicesome

method which allows identical hnRNA strands to give rise to slightly different mRNA, thus creating diverse array of proteins

mRNA leaves nucles after appropriate processing

1-allows RNA processing prior to translation

2-proteins made in modules that have functional domains corresponding to different exons

3-exon shuffling - rearrangement of exons in evolution whichi give a high probability forming new functional proteins